<template>
    <div>
        <router-link tag="div" to="/" class="header-abs" 
                     v-show="showAbs">
            <div class="iconfont header-abs-back">&#xe624;</div>
        </router-link>
        <div class="header-fixed" v-show="!showAbs" :style="opacityStyle" :key="Date.now()">
            <router-link to="/">
                <div class="iconfont header-fixed-back">&#xe624;</div>
            </router-link>
            景点详情
        </div>
    </div>
</template>

<script>
export default {
    name: "DetailHeader",
    data() {
        return {
            showAbs: true,
            opacityStyle: {
                opacity: 0
            }
        }
    },
    mounted() {
        window.addEventListener('scroll', this.handleScroll)
    },
    destroyed() {
        window.removeEventListener('scroll', this.handleScroll)
    },
    methods: {
        handleScroll() {
            const top = document.documentElement.scrollTop;
            // console.log(document.documentElement.scrollTop);
            if (top > 60 ) {
                let opacity = (top / 140)
                opacity = opacity > 1 ? 1 : opacity
                this.opacityStyle = {opacity}
                this.showAbs = false
            } else {
                this.showAbs = true
            }
        }
    }
}
</script>

<style lang="stylus" scoped>
    @import '~@/assets/styles/varibles.styl';
    .header-abs
        position absolute
        left .2rem
        top .2rem
        width .8rem
        height .8rem
        border-radius .4rem
        background rgba(0,0,0,.8)
        line-height .8rem
        text-align center
        .header-abs-back
            color white
            font-size .4rem
    .header-fixed
        z-index 2
        position: fixed
        top 0
        left 0
        right 0
        height: $headerHeight
        line-height $headerHeight
        text-align: center
        color: #fff
        background-color $bgColor
        font-size: .4rem
        .header-fixed-back
            position: absolute
            top: 0
            left: 0
            width: .64rem
            text-align: center
            font-size: .4rem
            color: #fff
</style>